1. Field of the Invention
This invention relates to a gas concentrator, and, more particularly, to an enhanced oxygen/gas concentrator utilizing a unique oxygen/gas concentration device providing instantaneous delivery of rich oxygen/gas concentrations to a patient.
2. Description of the Background Art
Resuscitation devices are used to temporarily emulate a patient's natural breathing. Resuscitation generally refers to externally applied assistance to supplement or restore an individual's respiratory activity. Resuscitation devices force oxygen-air mixtures through a patient's airway system to the lungs at staged intervals, while intermittently applying pressure to the patient's chest cavity inducing exhalation. "Squeeze bag" or "bag-valve-mask" resuscitators make use of some type of manually compressible and self-restoring bag in fluid communication with a face-mask. The operation of prior art resuscitation devices can be broken down into a two step process. First, the mask is applied to the face of a patient while manually squeezing the bag to force air from the bag through the mask and into the patient's lungs. Second, releasing the manually applied pressure from the bag and removing the mask from the patient's face to permit escape of air from the patient's lungs. During this step, the bag would self-inflate with atmospheric air through the mask. The bag would then remain in its restored condition until the next cycle, repeating as necessary. A squeeze bag resuscitator allows a trained person administering treatment to control the quantity and rate of air forced into the patient's lungs.
Squeeze bag resuscitators soon incorporated various refinements. To increase portability and facilitate use by a single person, resilient squeeze bags were adapted to be conveniently held in one hand with the face-masks attached directly to the frontal extremities of the bags. A one-way check valve in fluid communication with the interior of the bag and the atmosphere was introduced to permit refilling of the bag with fresh air during its restoration phase without removing the mask from the face of the patient. Additionally, the patient non-rebreathing valve assembly emerged. The assembly is located between the bag and the mask and permits fresh air to move from the bag into the mask during the squeeze phase, but vents to the atmosphere air returned to the mask from the patient's lungs during the bag restoration phase, preventing passage of the expired air into the bag from which it would be forced back into the patients lungs or "rebreathed" during the next squeeze phase.
During the course of development of squeeze bag type resuscitators, it was recognized that it would be desirable to administer pure oxygen, or at least oxygen enriched air, rather than merely atmospheric air, in treating some resuscitation patients. Accordingly, the development of a practical means for introducing oxygen into the squeeze bag initially entailed providing "oxygen enrichment" for the air drawn into the squeeze bag from the atmosphere during the restoration phase of the bag cycle. A common method for oxygen enrichment is to provide an elongate tube of relatively large diameter having one end in fluid communication with the fill valve opening of the bag and the other end exposed to the atmosphere, together with a considerably smaller tube extending into the larger tube and coupled with a pressurized oxygen source for continuously releasing oxygen into the air entering and accumulating within the large tube from the atmosphere. Such devices are referred to as "oxygen accumulators" and are effective to introduce air-oxygen mixtures into the bag during the restoration phase of its cycle, without significantly increasing the pressure within the bag. Examples of these and other oxygen accumulator resuscitators may be found in U.S. Pat. Nos. 4,501,271, 4,774,941, 4,821,713, 5,067,487, 5,109,840, 5,140,982 and 5,279,289. A shortcoming of resuscitators of this type is that the ambient air can dilute the concentration of the continuously flowing oxygen gas.
In the oxygen accumulator resuscitators described in U.S. Pat. Nos. 4,821,713, 5,067,487 and 5,140,982, two discrete, sequentially operable valves are provided to deliver the air/oxygen mixture, first into the tubular member and then into the face mask. Each valve has a comparatively high spring bias. The first valve can only be opened by releasing the squeeze bag from a compressed state, while the second valve is opened only by squeezing the bag. That is, the patient's spontaneous inspiratory efforts are not capable of operating the valves. This situation is exacerbated by the presence of the mask expiration port that is in direct fluid communication with the atmosphere which assures that insufficient negative inspiratory pressure can be developed in the mask to effect valve actuation.
Furthermore, the advent of the oxygen accumulator squeeze bag resuscitator did not satisfy the need for being able to administer substantially pure oxygen to patients under certain relatively frequently occurring high oxygen demand circumstances, such as resuscitation responsive to cardiac distress or like conditions. The invention disclosed in U.S. Pat. No. 3,796,216 attempts to administer essentially pure oxygen to a patient using a squeeze bag resuscitator. The apparatus included a body member, a squeeze bag, an oxygen inlet, a flapper valve and a face mask. The body member comprises a tubular portion to which the mouth of the squeeze bag is connected. The face mask is joined to the tubular member generally opposite the squeeze bag and an inlet adapted to be connected to a source of breathing gas, such as oxygen, is provided in the tubular member between the squeeze bag and the face mask. The flapper valve regulates passage of oxygen from the squeeze bag to the face mask.
Comparatively, the squeeze bag disclosed in U.S. Pat. No. 3,796,216 is not self-restoring, but is pliable and intended to be continuously inflated with oxygen. When the bag is sufficiently inflated and it is desired to administer oxygen to the patient, the administrator squeezes the bag to increase the pressure in the tubular member to a level sufficient to cause the flapper valve to expose a mask inhalation port and cover a mask exhalation port whereby the oxygen flows into the mask and then to the patient. Once the bag contents are depleted, i.e., the pressure in the body member is insufficient to overcome the bias of the flapper valve, the valve returns to its normal position covering the inhalation port and exposing the exhalation port. At this time, the patient exhales, his expiratory gases pass through the exhalation port and then the bag reinflates. This process is repeated until the patient breathes normally.
However, this type of system is incapable of dispensing pressurized atmospheric air in the event of failure or depletion of the pressurized oxygen supply. Specifically, even if the gas source were disconnected from the gas inlet thereby exposing the inlet to the atmosphere, the squeeze bag is not self-restoring. That is, the squeeze bag cannot create either the negative pressure required to draw air into the inlet or the positive pressure to expel the air. U.S. Pat. Nos. 2,399,643, 2,834,339, 3,196,866, 3,316,903, 3,473,529, 4,037,595, 4,077,404, 4,088,131, and 4,121,580 describe self-distending squeeze bag or similar resuscitators capable of administering air, oxygen or air-oxygen mixtures upon compressing the squeeze bag. Gas flow to and from the patient is effected by the opening and closing of at least one, and usually two or more, spring-biased check valves, flap valves or combinations of both. The resuscitators disclosed in U.S. Pat. Nos. 3,196,866 and 3,316,903 operate such that during expansion of the squeeze bag, the oxygen being supplied to the bag will always be mixed with atmospheric air because the resuscitator valve assembly includes ports in communication with the atmosphere and the interior of the bag, said ports normally being open and can only be closed by squeezing the bag. Thus, these resuscitators may together be envisioned as another form of the "oxygen accumulator" type resuscitators previously discussed. Moreover, resuscitators of this type are incapable of delivering pure oxygen which may at times be vital depending upon the needs of the patient.
Most of the other resuscitators provided in U.S. Pat. Nos. 2,399,643, 2,834,339, 3,473,529, 4,037,595, 4,077,404, 4,088,131 and 4,121,580 may effectively administer substantially pure oxygen. However, the valve assemblies are particularly complex in construction and heavily dependent upon the valve spring biases to effect proper resuscitator operation. Should the oxygen supply of such a resuscitator be temporarily interrupted, the patient would need to expend considerable inspiratory effort to draw atmospheric air into the resuscitator. The patient may be incapable of such exertion and only aggravate the respiratory distress.
Pressurized oxygen cannot easily be continuously introduced into a squeeze bag resuscitator without comprising other essential system functions. To circumvent these problems, assorted valving arrangements have been developed for introducing and interrupting the supply of pressurized oxygen into various parts of the resuscitator system. Such valving arrangements are intended to respond automatically to particular conditions of the resuscitator system, responding to sensing of differential pressures, and are commonly referred to as "demand oxygen supply valves". Despite their effectiveness, the demand oxygen supply valves disclosed are complicated in design and operation, costly to manufacture and, because of their numerous parts, susceptible to malfunction. Should any of these intricately interrelated components fail to function precisely as designed, oxygen administration will be detrimentally affected, if not totally interrupted.
Should the oxygen flow be interrupted for any reason, the patient would have ready access to the atmosphere by simply inhaling, thereby drawing the air through the second flapper valve and then the first flapper valve. To assure that ambient I air does not mix with the oxygen under normal operation, the spring bias of the second flapper valve has been intentionally designed to be rather significant. Because of this built-in bias, however, the patient may experience considerable resistance when it becomes necessary to breathe air directly from the atmosphere. For reasons mentioned above, the patient may not be able to summon the strength to overcome the bias of the second flapper valve and, consequently, the presence of the resuscitator may hinder rather than promote restoration of his normal respiratory activity.
It would be advantageous for a squeeze bag type resuscitator including an uncomplicated, substantially bias-free valve means capable of delivering essentially pure oxygen during normal operation while affording a patient unhindered access to atmospheric air if the oxygen flow ceases. Apart from the aforementioned deficiencies arising from the construction and/or function of their valve assemblies, optimal performances, versatility and operational convenience of conventional squeeze bag type resuscitator apparatus are encumbered by a number of other component-specific design limitations.
In addition to a squeeze bag, prior art systems include an oxygen reservoir bag upstream of the squeeze bag. The oxygen bag is preferably formed of thin, pliable plastic, which is not self-inflating. The oxygen reservoir bag is generally open at its opposite ends, which are taped or otherwise adhesively and sealingly secured to the upper and lower manifolds. The manifolds are respectively connected to the non-rebreathing valve and the squeeze bag, and are attached to opposite ends of the flexible hose whereby fluid communication is established between the manifolds through the flexible hose. So constructed, the oxygen reservoir bag defines a sealed oxygen chamber about the flexible hose and between the manifolds. A disadvantage of this arrangement is that the additional materials (e.g., tape or adhesive) and attendant labor required to adhesively secure the opposite ends of the oxygen reservoir bag to the manifolds undesirably contribute to the manufacturing cost of the resuscitator. Moreover, if care is not taken in the attachment of the oxygen reservoir bag to the manifolds, oxygen may leak from the system.
U.S. Pat. Nos. 4,917,081 and 4,919,132 teach pliable breathing gas storage bags connected at their opposite ends to components of respiratory apparatus. The bag in U.S. Pat. No. 4,919,132 merely receives smooth tubular inserts having no structure to which the bag may positively and sealingly engage to prevent gas leakage from the bag.
An advantage exists for an improved system by which the oxygen reservoir bag may be sealingly attached to the resuscitator without resort to adhesive tape or other superfluous fastening means. U.S. Pat. No. 4,501,271 illustrates a conventional, fully disposable resuscitator. Such apparatus is designed for one-time use, preventing cross-contamination. However, disposable resuscitators must be discarded in their entirety after a single use. Consequently, these systems are expensive and costly to maintain as inventory. Moreover, because many of the resuscitator components are subject to patient contamination, and are not sterilized after usage, these resuscitators are not considered to be particularly environmentally compatible.
Fully reusable resuscitators, as described in U.S. Pat. No. 2,834,339, are sterilizable and reusable. While these systems appear to be more economical, they require sterilization after each use. Consequently, considerable handling, disassembly, assembly and testing is needed to assure that the system is properly sterilized and continues to function properly.
U.S. Pat. Nos. Re. 24,193, 2,834,399, 3,196,866, 3,473,529 and 4,374,521 represent examples of squeeze bag resuscitators whose squeeze bags are self-sealingly or "stretchfit" onto the apparatus. None of these disclosures, however, address the economic, environmental and safety advantages that may be achieved through development of a partially reusable resuscitator, particularly one whose squeeze bag may be repeatedly sterilized and reused and whose other components may be discarded after each use.
A further advantage exists, therefore, for a squeeze bag resuscitator that permits ready sterilization and reuse of its most rugged, costly and yet most easily sterilized component, i.e., its squeeze bag, and which simultaneously affords convenient discardability of its other functional components as an integrated disposable assembly.
The present invention overcomes the disadvantages with these prior art systems, and provides a unique oxygen/gas ok concentrator adaptable for use in breathing devices, particularly resuscitators.
An advantage of the present invention is that simpler tooling devices are required to fabricate the manifold and gas distribution means, thereby reducing manufacturing costs.
Another, more specific, advantage of the present invention is to provide increased oxygen/gas concentrations.
Still another, more specific, advantage of the present invention is to provide faster oxygen/gas recovery times during low volumetric flow rates.
Yet another advantage of the present invention is to administer pure oxygen, or at least oxygen enriched air, rather than merely atmospheric air, in the treatment of some resuscitation patients.
Another advantage of the present invention is the ability to dispense pressurized atmospheric air in the event of failure or depletion of the pressurized oxygen supply.
Still another advantage of the present invention is to provide an overall safer breathing apparatus.
Yet another advantage of the present invention is that assembly time is reduced.
Another advantage of the present invention is to provide a more manageable gas concentrator.
Still another, more specific, advantage of the present invention is to provide a more manageable resuscitator.
Yet another advantage of the present invention is to provide a means for distributing gas within a gas reservoir.
Another advantage of the present invention is to provide a manifold within a gas reservoir.
Still another, more specific, advantage of the present invention is to provide a means for supplying a gas to a manifold within a gas reservoir.
Yet another advantage of the present invention is to provide a gas concentrator adaptable for use within a breathing device, comprising an elongate pliable reservoir, including a first opening and a second opening; a manifold including a first part and a second part, said first part being coupled to said second opening of said reservoir; a means for distributing gas throughout said reservoir, wherein said means is substantially encompassed by said reservoir and connected in fluid communication with said manifold; and, a means for supplying gas to said manifold, said supply means being connected and in fluid communication with said manifold, thereby supplying gas to said distributing means.
Another advantage of the present invention is to provide an apparatus for concentrating gas, adaptable for use within a breathing device, comprising an elongate pliable reservoir, including a first opening and a second opening; a manifold including a first part and a second part, said first part being coupled to said second opening of said reservoir; a means for distributing gas throughout said reservoir, wherein said means is substantially encompassed by said reservoir and connected in fluid communication with said manifold; and a means for supplying gas to said manifold, said supply means being connected and in fluid communication with said manifold, thereby supplying gas to said distributing means.
Still another, more specific, advantage of the present invention is to provide a system for concentrating and delivering gas, said system comprising a gas supply; an elongate pliable reservoir including a first opening and a second opening; a manifold including a first part and a second part, said first part being coupled to said second opening of said reservoir, wherein said manifold further comprises a gas check valve and an air check valve, said gas check valve located between and being in fluid communication with said distributing means and said supply means, wherein said air check valve is in fluid communication with the atmosphere, and, wherein said gas check valve and said air check valve manifest an inflow state and a restricted state; a means for distributing gas throughout said reservoir, wherein said distributing means comprises a first end, a sealed second end, and a plurality of uniformly distributed perforations located substantially adjacent to said first end of said distributing means, wherein said first end of said distributing means is connected to said first part of said second manifold, said distributing means being substantially encompassed by said reservoir; and a means for supplying gas to said manifold, said supply means being connected and in fluid communication with said manifold and said gas supply, thereby supplying gas to said distributing means.
The foregoing has outlined some of the pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.